Sewing machine



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SEWING MACHINE 4/2222 Man-4 fliiorn cf ytf 8. W. AVIS SEWING MACHINE Jan. 9, 1940.

Filed Jan. 27, 1958 12 Sheets-Sheet l2 pm M d i Eva Z w h i l EW J W NN I i Haw. M m m m imfiufiw w .v T m F Q w w T 4 EU raw J u l m 2 ww w A iw ww w wmmfi: QNQIMFI N NQNL2I uw Li WWWL--- A N \md m S 2 Patented Jan. 9, 1940 UNITED STATES PATENT OFFICE The Reece Button Hole Machine Company,

Boston, Mass., a corporation of Maine Application January 27, 1938, Serial No. 187,175

-62 Claims.

This invention relates generally to sewing machines and more particularly to sewing machines of that type which are used for making a "tack at the end of a button hole slit or a pocket slit in garments or any other places where a reinforcing tack is desirable.

It is among the objects of the present invention to provide a sewing machine which is capable of forming a tack of variable dimensions within limits defined only by the limits of adjustment of certain elements of the machine. More particularly, the machine shall be so universally adjustable as to vary the overall length of the tack, and/or its number of underlying stitches, and/or its number of overlying stitches and/or the width of the overlying stitches.

It is another object of the present invention to provide a sewing machine of the above type in which the material remains stationary and the sewing elements of the machine are moved relative to the material for the formation of a tack.

It is another object of the present invention to provide novel structure in a sewing machine of the above type for automatically severing both the needle thread and the bobbin thread from their supplies at the end of a tacking operation, leaving thereby a sufficient length of upper thread in the needle to complete a lock stitch on the first reciprocation of the'needle during the following tacking operation.

It is also among the objects of the present invention automatically to clamp the severed or leading end of the bobbin supply thread to the throat plate of the machine, so that the bobbin thread may immediately form a lock stitch together with the loop. of upper thread which is cast by the needle on its first reciprocation during the next tacking operation.

Before explaining in detail the present invention it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation, and it is not intended to limit the invention claimed herein beyond the requirements of the prior art. In the drawings: Fig. 1 ill trates an example of a tack made by a-machine which embodies the present invention.

' one of two identical Fig. 2 is a vertical section through the machine which embodies the present invention. More particularly this section is taken on the line 2-2 of Fig. 4.

Fig. 3 is another vertical section through the machine, taken substantially on the line 3-3 of Fig. 4.

Fig. 4is a horizontal section through the machine, taken substantially on the line 4-4 of Fig. 3.

Fig. 5 is a fragmentary section through one of the clutches of the machine, taken substantially on the line 5-5 of Figs. 4 and 6.

Fig. 6 is a fragmentary section through the same clutch taken substantially on of Fig. 5.

Fig. 7 is a fragmentary section similar to Fig. 5, showing certain elements of the clutch in different positions of cooperation, however.

Fig. 8 is a horizontal section through the machine, taken substantially on the line 8-8 of Figs. 2 and 3.

Figs. 9 and 10 are fragmentary sections, taken on the lines 9-9 and Ill-I0, respectively, of Fig. 8.

Fig. 11 is an enlarged fragmentary section, taken substantially on the line I l-.|l of Fig. 3. 'Fig. 12 is an enlarged fragmentary section, taken on the line l2l2 of Fig. 3.

Figs. 13 to 15, inclusive, are fragmentary sections taken substantially on the lines l3l3, "-44 and l5-l5, respectively, of Fig. 3.

Fig. 16 is an enlarged fragmentary section through certain cooperating elements of machine.

Fig. 1'? is a diagrammatic view, illustrating one of two identical intermittent rises in each convolution of the continuous groove of a screwtype feed cam of the machine.

Fig. 18 is an enlarged section, taken substantially on the line l8'-l8 of Fig. 16 and showing a follower in cooperation with the rise illustrated in Fig. 17.

Fig. 19 is a diagrammatic view, illustrating intermittent rises in each convolutio of the continuous groove of another screw-t eed cam of the machine.

Fig. 20isan enlarged section through a follower which cooperates with the cam element shown in Fig. 19. I i

Fig. 21 is an enlarged, fragmentary section, taken on the linen-2i of Fig. 3.

Fig. 22 diagrammatically illustrates the invar able coordination enstins the line 6-4 1 the between certain elements of the machine which operate in timed relation and one of which is adjustable.

Fig. 23 is a fragmentary plan view of a small portion of the machine, particularly that portion thereof which is encircled by the dot-and-dash line 23 in Fig. 4.

Fig. 24 is a front elevation of the structure shown in Fig. 23.

Fig. 25 is a drawn-out perspective view of the .main cam shaft of the machine as viewed in the direction of the arrow 25 in Fig. 4.

Figs. 26 and 26a show certain detail structure of the machine which cooperates to index the cam shaft in Fig. 25 at the proper times in the cycle of operation of the machine.

Figs. 27 to 30, inclusive, are detail views of certain cams mounted on the main cam shaft.

Fig. 31 is a greatly enlarged, fragmentary section, taken substantially on the line 3l--3l of Fig. 2.

Fig. 32 perspectively illustrates the shfortly occurring severance of the upper and lower threads from their supplies and the anchorage of the leading or severed end of the upper and lower thread supply to the throat plate of the machine.

Fig. 33 is a greatly enlarged, fragmentary section, taken substantially on the line 3333 of Figs. 2 and 31.

Fig. 34 is a fragmentary section similar to Fig.

33, showing the elements in different positions of cooperation, however.

Fig. 35 is a fragmentary section, taken on the line 3535 of Fig. 33. i

Fig. 36 is a fragmentary section, taken substantially on the line 36-36 of Fig. 3.

Fig. 37 is an enlarged fragmentary section through a certain clutch of the machine.

Figs. 38 to 46, inclusive, diagrammatically illustrate certain coordinated positions between the needle crank and'two feed cams of the machine.

Fig. 47 is a chart which graphically illustrates the timed relation of certain major operations performed by the machine during one cycle of operation of the same.

Referring to the drawings, the machine therein illustrated forms a tack of variable dimensions within limits defined only by the limits of adjustment of certain elements of the machine. An example of a tack produced by the present machine is illustrated in Fig. 1, and consists of four superimposed lines or rows of underlying stitches a and a row of overlying or cover stitches b. The underlying as well as overlying stitches are all lock stitches as evidenced by the showing of a shuttle in the drawings, but chain stitches could be used in the formation of thetack if desired, as will be more fully explained hereinafter.

The supporting structure of the present machine comprises three frames 50, and 52 (Fig.

3) which are mounted together in any suitable manner and support the various operating devices of the machine. More particularly, the base frame 56 supports the other frames 5| and 52 which will be hereafter referred to as the hom and head, respectively, of the machine. The various operating devices of the machine, which are supported by the frames 50, 5| and 52, may be termed as follows: the needle reciprocating device A (Fig. 2), the rotary drive B for the thread handling element (Fig. 3), the feeding device C for the needle and thread handling element longitudinally of the tack (Fig. 3), the

needle vibrating device D (Fig. 3), the thread severing and clamping device E (Figs- 33 to 35;

inclusive), and the control F for the proper operation of the preceding devices (Fig. 25)

Needle reciprocating device A As best shown in Fig. 2, the needle 53 is carried by a needle bar 54 which is axially reciprocable in bosses 55 of a yoke 56 that is provided with a hollow shank 51. The shank 51 is rotatably mounted in an outer sleeve 58 which is in turn axially slidable in a boss 59 of the head 52 of the machine. Any suitable means, such as a pin and slot between the boss 59 and the sleeve 58 (not shown), may be used in order to prevent rotation of said sleeve, yet permit axial movement of the same in the boss 59. A collar 60, suitably secured to the shank 51 of the yoke 56 and engaging the adjacent end of the sleeve 58, retains the opposite end of the latter in permanent engagement with an annular shoulder 6| of the yoke 56, wherefore said yoke 56 is axially movable toether with the sleeve 58. Rotatable in the hollow shank 51 of the yoke 56 and a coaxially aligned sleeve 62 is the needle-crank shaft 63, a reduced end 64 of which extends beyond the yoke 56 and the opposite end of which is provided with a hand wheel 65 on the ouside of the head 52. Mounted on the reduced shaft portion 64 1s a crank disc 66 which has the usual pitman connection 61 with the needle bar 54 in order to reciprocate the latter. Journalled on the reduced shaft portion 64, and interposed between the crank disc 66 and the yoke 56, is a member 68, the function of which will be described hereinafter. The annular shoulder of the needle crank shaft 63 is held in permanent engagement with an annular shoulder 12 of the yoke by the crank disc 66 and the member 68, wherefore the needle shaft 63 is axially movable in either direction togizther with the yoke 56 and the sleeve 58, as a un While the needle shaft 63 may be manually rotated at any time by the hand wheel 65, the same is ordinarily power-driven and connected with any suitable prime mover by means of a clutch 14. The clutch 14 is in reality a double clutch, to wit, a main clutch and a sewing clutch. The prime mover may be an electric motor (not shown) which is connected by a belt 16 (Fig. 4) with a pulley 18 that is either drivingly connected, or integral, with another pulley 80. The pulleys 18 and 80 are rotatably mounted in any suitable manner on the outside of the base frame 50, and the pulley 80 drives another pulley 82 by means of a belt 84. The pulley 82 is mounted on the earlier mentioned sleeve 62 (Fig. 2) through which the needle shaft 63 extends. Keyed or otherwise secured to the sleeve 62 as at 86 (Fig. 5) is the common driver 88 of the double clutch 14. The sleeve 62 itself is journalled in a bearing bracket 96 which is suitably mounted at 92 on the head 52 (Fig. 2). The common driver 88 of the double clutch 14 is a disc, provided with annular recesses 94 in its opposite faces in which are located portions of the two driven members 96 and 98 of the main clutch and sewing clutch, respectively. More particularly, the driven member 96 of the main clutch is freely rotatable on the sleeve 62, while the driven member 98 of the sewing clutch is mounted on the needle-crankshaft 63 and provided with a tubular extension I60 which projects into the hollow shank 51 of the yoke 56 and is internally splined at I (ll to the needle shaft 63. The common driving member 88 as.

well as the driven members 96 and 98 of the clutch 14 are held axially immovable.

Inasmuch as the main clutch and the sewing clutch are of the same construction and operation, only the latter clutch will be described in tion I06 of a dog I08 which is normally urged into engagement with an inclined shoulder IIO in the rim II2 of the driving member 88 by means of a spring II4, anchored at H6 in the driven member 98 and received in grooves H8 16 and I20 of said driven member and the dog I08,

respectively. The driving member 88 normally rotates in a clockwise direction as viewed in Fig. 5, so that its rotary motion is transmitted to the driven member 98 through the inclined shoulder H0 and the dog I08. The driven member 98 is disengaged from the driving member 88 by a shifter I22 which is journaled 'on a horizontal shaft I26 (Fig. 4), suitably supported in a bracket I28 and a boss I30 of the head 52.

The shifter I22 is centrally recessed at I32 (Fig.

'6) to receive a plunger I34. A pin I36 is secured to the plunger I34 and extends with its two opposite ends into two diametrically opposite slots I38 in the shifter I22, A spring,I40 is 10- cated in the recess I32 and normally urges the plunger I34 to the right as viewed in Figs. 5 and 6, i. e., into a position in which the pin I36 engages the right end walls of the slots I38 as viewed in Fig. 6. While the clutch members 98 and 88 are engaged, the shifter I22 is out of the path of rotation of the dog I08, a portion of which projects beyond the rim II 2 of the driving member 88. On rocking the shifter I22 into the position shown in Fig. 5, the plunger I34 is 40 brought into the path of rotation of the dog I08 and rocks the same counter-clockwise as viewed in Fig. 5 into the position shown in Fig. '7 in which the dog engages a machined surface I42 of the driven member 98 and clears the inclined 45 shoulder IIO of the driving member 88, thus causing clutch disengagement. The spring I40 will momentarily yield and considerably cushion theimpactbetween the plunger I34 and the dog I08 when the clutch 88, 98 is disengaged. In

order to prevent the driven member 98 from backing-up even slightly in its disengaged position and thereby perhaps occasion an unauthorized reengagement of the clutch, a, latch I44 is pivotally mounted on the shifter I22 and continuously urged against a stop pin I46 by a spring I48. While the plunger I34 knocks the dog I08 from driving engagement with the inclined shoulder IIO, an inclined surface I50 of a pin I52 in the driven member 98 cooperates 0 with an inclined surface I54 of the latch I44 in the manner shown in Fig. 5, thereby rocking said latch out of the path of rotation of said pin until the latter clears the former, whereupon the latch snaps into engagement with a machined flat I56 of said pin I52, i. e., just when the dog I08 has been forced into engagement with the surface I42 of the driven member 98 (Fig. 7). Hence, the driven member 98 is arrested against rotation in any direction immediately upon clutch disengagement. To reengage the driven member 98 with the driving member 88, the shifter I22 is rocked in the opposite direction so as to withdraw the plunger I34 from engagement with the dog I08, whereupon the spring I44 forces said dog into reengagement with the inclined shoul:

der I I0 0! the driving member 88. On rocking the shifter I22 into clutch-engaging position, the latch I44 is also immediately withdrawn from the pin I52 due to the engagement of the former with the stop pin I46 on the shifter I22.

The sewing clutch 88, 96 is engaged and disengaged by a shifter I58 (Fig. 4) which is of the same construction, and performs in the same manner, as the shifter I 22. The shifter I58 is also freely rotatable on the shaft I26.

Rotary drive B for the thread handling element The thread handling element in the horn SI of the machine is shown in form of a shuttle I60 (Fig. 2) which is mounted on a combined support and drive I62 that forms the subject matter of my co-pending application Serial No. 185,- 538, filed January 18, 1938, and consists essentially of angularly spaced pawls I64 which are pivotally mounted on a rotary carrier I66 and enter apertures I68 in the shuttle periphery (Fig. 35) in such alternate fashion that,a needlethread loop I10 (Fig. 32), which is completely passed around the shuttle by its hook I12, need not be twisted, nor is interfered with by the pawls I64, all as described in my above-mentioned co-pending application. The pawls I64 are in permanent engagement with a continuous camsurface I14 (Fig. 35) which is provided by a cylindrical block I16, hereafter called the cam block, and is so designed that the pawls I64 enter their respective apertures I68 in the shuttle periphery in the above mentioned alternate fashion. To accomplish such cooperation between the cam surface I14 and the pawls I64, the cam block I16 is held non-rotatable, while the pawl carrier I66 is rotated. Rotation of the cam block I16 is prevented by the throat plate I18 which is guided for movement longitudinally of the tack in guldeways I (Fig. 31) in the work table I82, and drivingly connected with the cam block I16 by any suitable connection such as a pin I84 and a spacer I86 (Figs. 33 to 35), for instance. The throat plate I18 thus indirectly prevents rotation of the cam block I16 inits cylindrical support I88, provided by the horn 5| of the machine.

A ball bearing I90 is interposed between the pawl carrier I66 and the cam block I16. A nut I92, which is threadedly received by the pawl carrier I66, retains an annular shoulder I94 of the latter in permanent engagement with the inner race 196 of said ball bearing I90 (Figs. 2 and 35). On the other hand, the outer race I98 of the ball bearing I90 is retained in permanent engagement with an annular shoulder 200 of the cam block I16 by means of the head 202 of a sleeve 204 which is secured in any suitable manner as at 206 (Fig. 2) to the cam block I16. It is,- therefore, obvious that the pawl carrier- I66 will move axially together with the cam block I16 asa unit when the latter is axially fed longitudinally of the tack in order to form the various stitches of the tack. A reduced end portion 208 of the sleeve 204 is slidably supported in a boss 2I2 of the horn 5| of the machine. Splined at 2 to the pawl carrier I66 is one end of a rotatable, but axially immovable, shaft 2I6 which-has its other end joumalled in a ball bearing 2I8 (Fig. 2). The ball bearing 2I8 is located in a bracket 220 of the horn 5| and held therein by a retainer 222. A bevel gear 224 and a nut 226, both secured to the shaft 2I6, engage the inner race 228 of the ball bearing 2I8 and thus prevent axial movement of the shaft 2I6. The 7.5;

gears 248 and 238 is two to one.

bevel gear 224 is in permanent mesh with another, identical bevel gear 238 which is mounted on a transverse shaft 232 (Figs. 3 and 8), suitably journalled in suitable bearing brackets 234 and 236, the latter being shown integral with the base frame 58. Also mounted on the transverse shaft 232 is another bevel gear 238 which is in permanenthmesh with a larger bevel gear 248, mounted on a horizontal shaft 242 which is suitably journalled in the before-mentioned bearing bracket 236 and another bracket 244 (Fig. 3) which is preferably integral with the base frame 58. The ratio between the bevel Also mounted on the vertical shaft 242 is another bevel gear 245 which is in permanent mesh with an identical bevel gear 246, mounted on a horizontal shaft 248 (Fig. 4). The shaft 248 is suitably journalled in the before-mentioned bearing bracket 244 and another bearing bracket 258 which is mounted in the head 52 of the machine. Also mounted on the shaft 248 is a bevel gear 252 which is in permanent mesh with an identical bevel gear 254 that is either drivingly connected, or integral, with the driven member 98 of the sewing clutch 88, 98. Hence, whenever the clutch 88, 98 is engaged, i. e.,- when the needle shaft is rotated and the needle bar reciprocates, the pawl carrier I66 and the shuttle I68 are rotated through intermediation of shaft 2I6, bevel gears 224 and 238, shaft 232 (Fig. 3), bevel gears 238 and 248, shaft 242, bevel gears 245 and 246, shaft 248 (Fig. 4) and bevel gears 252, 254. However, inasmuch as the ratio between the bevel gears 248 and 238(Fig. 3) is two to one, it follows that the shuttle I68 makes two complete revolutions to each rotation of the needlecrankshaft 63, i. e., each reciprocation of the needle bar 54. In other words, the shuttle hook I12 (Fig. 32) catches each loop which is cast by the needle 53 after each second revolution of the shuttle. The reason for rotating the shuttle I68 at twice the speed of the needle crank shaft 63 is fully explained in my before-mentioned co-pending application Serial No. 185,538, and hence requires no explanation here.

While the drawings illustrate a shuttle I68 for the formation of lock'stitches such as shown in Fig. 32, it is to be distinctly understood that the rotary looper disclosed in my before-mentioned co-pending application could be used for the formation of chain stitches, if so desired.

Feeding device C for needle and thread handling element Inasmuch as the work W (Figs: 1 and 2) redriving elements to be described. As best shown in Fig. 14, the rack bar 268 is slidable on the machined surfaces 262 of vertically spaced brackets 264 which are mounted in any suitable manner on horizontal flanges 266 of an upright support 268 which is mo ted in any suitable manner as at 218 on a sid wall of the base frame 68.. The rack bar 268 is urthermore guided for and in the same directions.

vertical movement by straps 212 (see also Figs. 11 and 12) which are suitably secured to the brackets 264. It appears best from Fig. 14 that the rack bar 268 provides at its opposite ends two racks'214 and 216, one of said racks being 5 adapted to feed the yoke 56 and the other rack being adapted to feed the shuttle support and drive I62; The manner in which the rack bar 268-is power-reciprocate'd will be described later in the description.

The following structure transmits the movement of the rack 214 to the yoke 56. Cooperating with the rack 214 is a spur gear 218 (Figs; 3 and 4) which is mounted on a horizontal shaft 288, journalled in bearings provided by a suit- 15 ably mounted bracket 282 and a boss 284 of the machine head 52. Mounted on that end of the shaft 288 which projects into the head 52 is a rocker arm 286 (see also Fig. 2) which is connected with an identical rocker arm 288 on a 20 counter shaft 298 by means of a link 292. The. counter shaft 298 is journalled in suitable bearing brackets 294 in the machine head 52 and carries a spur gear 296 which is in permanent mesh with a rack 298, provided in the sleeve 58. 25 Consequently, the sleeve 58 and the yoke 56 aremoved axially in opposite directions on reciprocation of the rack 214, as can be readily understood.

The following structure transmits the movement of the rack 216 to the shuttle support and drive I62. Cooperating with the rack 216 is a spur gear 388 (Figs. 3 and 8) which is mounted on a horizontal shaft 382, journalled in bearing brackets 384 and 385 which are mounted on 35 the support 268 and in the horn 5I of the machine, respectively. Mounted on that end of the shaft 382 which extends beyond the bearing bracket 385 is a rocker arm 386 (Figs. 2 and 8) which is connected by a link 381 to another rocker 40 arm 388, mounted on a stub shaft 389 which is journalled in abearing bracket 3 I 8 and a boss 3| I of the horn 6|. Mounted on the stub shaft 389 between the bearingbracket 3I8 and the boss 3| I is a spur gear 3I2 which is in constant mesh with 45 a rack 3I3, provided by the reduced end 288 of the sleeve 284. Hence, the'sleeve 284 and the shuttle support and drive I82 are moved axially in opposite directions on reciprocation of the rack 216.

The motion transmitting elements of each of the drives described in the two preceding paragraphs are so coordinated that the yoke 56 with its needle bar 54 as well as the combined support and drive I62 of the shuttle I68 are simul- 55 taneously axially moved through equal distances More particularly, the yoke 56 and the shuttle support and drive I62 are moved or fed to the left as viewed in Fig.

2 on upward movement of the rack bar 268 as 60 viewed in Fig. 14. Conversely, the yoke 56 and the shuttle support and drive I62 are fed to the right as viewed in Fig. 2 on downward movement of the rack bar 268 as viewed in Fig. 14.

Two rotary and alternately operative 'screw- 5 type feed cams 3I5 and 3| 6 are called upon for reciprocating the rack bar 268. A common drive,

'to be described, between the rack bar 268 and the feed cams 3I5, 3I6 is in permanent driving relation with the former and in alternate driv- 7 ing relation with the latter. As best shown in Figs-12 to 15, inclusive, the feed cams 3| 5 and 3I6 are mounted on vertical shafts 3I1 and 3l3, respectively, which are journalled in a swinging frame 328, mounted on the upright support 268 the latter resting on the swinging frame 328, thus cooperating with a collar 332 to prevent axial movement. of the shaft 322 relative to the frame 828. Mounted at the upper end of the shaft 3" (Fig. 14) is a spur gear 334 which rests with its hub 336 on the swinging frame 328. Mounted on the upper end of the shaft 3l8 is a gear 338 (Fig. 13) which rests on the swinging frame 328. As best shown in Fig. 11, gear 328 is in constant mesh with gear 334, while gear 338 is in constant mesh with gear 338. The ratio between the gears 328 and 334 is one to one, while the ratio between the gears 338 and 338 is one to two. Consequently, on rotation of the bevel gear 326, the feed cam 3l5 is rotated at the same angular speed as said bevel gear 326, while the cam' element 3l6 is rotated at one-half the angular speed of said bevel gear. Furthermore, the feed cams 3I5 and 3 l 6 rotate always in the same directions. I Each of the feed cams 315, 3 l6 has two diametrically opposite rises in each annular groove portion (Figs. 13 and 14), thus forming a continuous cam groove 348 in the feed cam 3l5 and a continuous cam groove 342 in the feed cam 3l6.

Permanently meshing with diametrically opposite portions of the bevel gear 326 (see Figs. 3 and 4) are smaller bevel gears 344 and 346 which are freely rotatable on a horizontal shaft 348, journalled in bearings provided by bosses 358 of the base frame 58 and head 52 of the machine. The bevel gears 344 and 346 are provided by the driven members 352 and 354, respectively, of a reverse clutch 356, the driving member 358 of which is splined to the shaft 348 and axially movable thereon into alternate engagement with the driven members 352 and 354. The clutch shaft 348 carries a bevel gear 368 which is in permanent mesh with a bevel gear 362 that is either drivingly connected, or integral, with the driven member 86 of the main clutch 88, 86. Hence, on engaging the main clutch, the rotary motion of the driving member 88 of said main clutch is transmitted to the driving member 358 of the reverse clutch 356 through intermediation of thefbevel gears 362 and 368 which have a ratio of one to one, and the shaft 348.

Slidable in vertical guideways 366 and 368 of the upright support 268 (Figs. 11 to 14) are racktype followers 318 and 312 which are adapted to cooperate with the screw-type feed cams 3l5 and 316, respectively. The cam element 3l5 is used for spacing the underlying stitches a longitudinally of the tack as shown at c in Fig. 1, for instance. Conversely, the cam element 3l6 is used for spacing the overlying stitches the distance d as shown in Fig. 1. The rises 314 of the feed cam 3l5 are preferably of the harmonic, shape shown in Fig. 17. Likewise, the rises 318 of the feed cam 3l6 are also of harmonic shape as shown in Fig. 19, but are only half as long and half as high as the rises 314 of the feed cam 3l5. Inasmuch as the followers 318 and 312 have to remain in cooperative engagement with their cam elements 3l5 and 316, respectively, during the formation of their respective underlying and overlying stitches, the teeth 382 and 384 of said followers 318 and 312, respectively, have to be of the rhomblc cross-sectional shape shown in Figs. 18 and 28, respectively.

As the underlying stitches a are the first to be formed, it is the feed cam 3l5 which is in cooperative engagement with its follower 318 when the machine is started (Figs. 12 and 14). Then, depending on the direction of rotation of the feed cam 3l5, the follower 318 will either move upwardly or downwardly. As best shownin Figs. 3, 14 and 21, a lever 386, located between the rack bar 268 and the upright support 268, has a hollow shank 388 (Fig. 21) which is journalled in said support 268 and the base frame 58. The lever 385 is provided with an elongated slot 388 in whlch a rectangular block 382 is slidable. The block 382 is pivoted on the shank 384 of a screw 385 which extends through a vertical slot 385a in the upright support 268 and is secured to the follower 318. The lever 386 is also provided with guioeways 386 for a rack 381 which is in permanent mesh 'with a gear portion 388 of a short shaft 388, rotatable in the hollow shank 388 of the lever 386. Keyed at 488 to the shaft 388 is an index disc 48!, having a series of radial serrations 482 one of which registers with a radial tooth 483 of corresponding cross sectional shape, provided by a counter disc 484 which is keyed at 485 to the shank 388 of the lever 386. A nut 486, threadedly received by the shaft 388, is tightened against the index disc 48 I thereby not only 4 in a transverse extension 4l5 of the rack bar 268 (Fig. 3). the lever 366 is rocked in a certain direction, depending on the direction of rotation of the feed cam 3l5, and that the block 4I3, which rocks with the lever 386, moves the rack bar 268 in the same direction as the direction of movement of the follower 318.

It may be stated in advance that the needle bar 54 and the shuttle I68 assume the rear or It can now be understood that home position shown in'Fig. 2 when the machine is at rest. Consequently, on starting an operation of the machine, the needle bar 64 and the shuttle I68. will be fed step by step from the illustrated home position in Fig. 2 to the left,

- such forward feed of the needle bar 54 and shuttle I68 taking place during an upward motion of the rack bar 268, as has been earlier explained. It appears from Figs. 12, 14 and 21 that such upward movement of the rack bar 268 is obtained on rotating the feed cam 3 I 5 clockwise as viewed in Fig. 12. In order to rotate the feed cam 3l5 clockwise as viewed in Fig. 12, the members 352 and 358 of the reverse clutch 356 (Fig. 4) have to be engaged, assuming thereby that the driven member 86 of the main clutch 88, 86 rotates in the direction of the arrow 428 in Fig. 4. The

drive between the driven member 86 of said main clutch and the feed cam 3l5 then comprises the bevel gears 362 and 368, shaft 348, the bevel gears 348 and 326 (Fig. 4), and the gears 328, 334. After the formation of the first line at of underlying stitches a, i. e., when the needle bar 54 and the shuttle I68 have arrived in their foremost position, the direction of rotation of the feed cam 3l6 is reversed so as to effect the return ing or home position shown in Fig. 2, thereby forming the second line a2 of underlying stitches a. To accomplish this, the driving member 358 of the reverse clutch 356 is shifted from engagement with its driven member 352 and into engagement with its driven member 354 under the action of certain controlling means to be described hereafter.

As will be more fully explained hereinafter, the construction of the present machine is such that the formation of the underlying stitches a is concluded and the formation of the overlying or cover stitches b, is started when the needle bar 54 and the shuttle I68 are in the starting position shown in Fig. 2. Consequently, it is at this time that the frame 328 is rocked so as to disengage the feed cam 3| 5 from its follower 318 and to engage the feed cam 316 with its folwith a, gear portion 429 of a short shaft 438,

received in the hollow shank 426. The shaft 438 has keyed thereto at 43l an index disc 432, 4

having a plurality of radial serrations 433, one of which registers with a radial tooth 434 of corresponding cross sectional shape which is provided by a counter disc 435. This counter disc 435 is keyed at 436 to the shank 426 of the lever 425. A nut 431 is threadedly received by the sha t 438 and tightened'against the index disc 4 x thereby not only retaining an annular shoulder 438 of said shaft in permanent engagement with an annular shoulder 439 of said shank 426, but also retaining the tooth 434 in registry with its serration 433, thus locking the shaft 438 to the lever 425 for combined rotation. As best shown in Fig. 14, the lever 425 is located between the rack bar 268 and the upright support 268. The rack 428 is provided with a lateral extension 448 (Fig. 12) which receives a screw 44l, the shank 442 of which serves as a pivot for a rectangular block 443, received in an elongated slot 444 in a transverse extension 445 of the rack bar 268 (Fig. 3). Hence, when the rotating feed cam 3|6 is in cooperative engagement with its follower 312, the movement of the latter is transmitted to the rack bar 268 through intermediation of the rectangular block 423, the plvotally mounted lever 425 and the rectangular block 443.

More particularly, clockwise rotation of the feed cam 3l6 as viewed in Fig. 12 will cause upward motion of the rack bar 268, i. e., cause a forward feed of the needle bar 54 and shuttle I68 from the starting position shown in Fig. 2 for the spacing d of the overlying stitches b (Fig. 1). Rotation of the feed cam 3l6 in the opposite direction will, conversely, cause a downward movement of the rack bar 268 and a consequent return feed of the needle bar 54 and the shuttle I68 into the home position shown in Fig. 2. The reversal of the feed cam 3l6 is accomplished, under the automatic control of means to be described later, by shifting the driving member 358 of the reverse clutch 356 from engagement with one of its driven members (352, 354) and into engagement with the other driven member. Because both of the feed feed of said needle bar and shuttle into the startcams 315 and 3| 6 are carried by the swinging frame 328 (Fig. 12) it stands to reason that only one of the followers 318, 312 may at any time be in engagement with its feed cam 3l5 or 3l6, respectively, thereby effecting movement of the rack bar 268 under the control of either feed cam without interference. from the other feed cam which is then out of engagement with its follower.

It can also be understood that the reciprocatory motion of the rack bar 268 is comparatively fast when under the control of the feed cam 3I5 (for the underlying stitches), because the block 3 92 (Fig. 21) is comparatively close to the pivot axis 458 of the lever 386, the rocking motion of which is transmitted to the rack bar 268 by the block 3 in form of a reciprocatory motion. On the other hand, the reciprocatory motion of the rack bar 268 is comparatively slow when under the control of the feed cam 3| 6 (for overlying stitches), because the block 423 (Fig. 12) which is carried by the follower 312, is comparatively distant from the pivot axis 45! of the lever 425, the rocking motion of which is transmitted to the rack 'bar 268 by the block 443 in form of a reciprocatory motion. The difference between the different speeds of reciprocation of the rack bar 268 under the different controls of the feed cams 3l5 and 3| 6 is even increased by reason of the fact that the former rotates twice as fast as the latter, and the rises 314 of the feed cam 3I5 are moreover twice as high as the rises'318 486 sufliciently to permit axial withdrawal of the index disc 48! until the presently registering serration 482 of' the latter clears the tooth 483 of the counter disc 484, whereupon the shaft 399 together with the index disc 48l may be turned relative to the counter disc 484 and, hence, relative to the lever 386. Thereafter, the index disc 48! is again locked to thecounter disc 484 by the nut 486, whereby a new serration 482 will be in registry with the tooth 483. Likewise, if it is desired to vary the rate of reciprocation of the rack bar 268 while the same is under the control of the feed cam 3I6, the just described operation is performed on the index disc 432 (Fig. 12) in order to shift the rack 428 in its guideways 421 into the desired position.

In order to assure instantaneous mesh between the feedvcams 3I5, 3| 6 and their respective followers 318 and 312, the continuous cam grooves 348 and 342, respectively, of the former, as well as the teeth of the latter, are preferably of the conical cross-section shown in Fig. 16.

Needle vibrating device D It appears from Fig. 1 that the needle 53 has to be laterally vibrated in order to formthe overlying stitches b. This is accomplished by oscillating the yoke 56' (Fig. 2) about the axis 455 while the same is simultaneously fed step by step for spacing the overlying stitches the distance d (Fig. 1) longitudinally of the tack. To

amazes this end, the yoke 56 is connected with a rocking lever 456 (Figs. 2, 3 and 4) by means of a link 451. The rocking lever 456 is provided by a sleeve 458 (Fig. 36) which is journalled in a boss 459 of the head 52 of the machine. Telescoping with the sleeve 458 and freely rotatable therein is a stub shaft 466 which has one end journalled in a bearing bracket, provided by the head 52 of the machine. Mounted on the stub shaft 466 is a rocker arm 462 which is pivotally connected at 463 with an arm 464, carrying a follower 465 which cooperates with a cam groove 466 in a disc 461, mounted on a shaft 468 which is journalled with one end in a boss 469 of the head 52 and with its other end in a sleeve portion 416 of the driving member 41I of a needle-vibration clutch 412. The sleeve portion 416 of the driving clutch member 41! is joumalled in a bearing bracket 413 in thehead 52 of the machine. The follower arm 464 is provided with a rectangular slot 414 wherein a rectangular block 415 is slidably received. The block 415 is freely rotatable on the shaft 468. Hence, the block 415 in the slot 414 forms a floating pivot for the follower arm 464. The cam disc 461 is drivingly connected, or integral, with the driven member 416 of the sewing clutch 412 which may be of the same construction and operation as that disclosed in Figs. 5, 6 and '1. The driving clutch member 41I is drivingly connected, or integral, with a bevel gear 418 which is in permanent mesh with a bevel gear 419, mounted on the shaft 248. The ratio between the bevel gears 418 and 419 is two'to one so that, on engagement of tie sewing clutch 88, 98 and of the vibration clutch 412, the cam disc 461 makes one half revolution to each complete reciprocation of the needle bar 54 and to every two revolutions of the shuttle I66. The rocker arm 462 is provided with a semi-cylindrical sleeve 486 which is in constant coupling engagement with a similar semi-cylindrical portion 48f of the sleeve 458 (Fig. 36). Hence, when .the clutch 412 is engaged, the needle bar carrying yoke 56 is oscillated through intermediation of link 451, rocker arm 456, coupling I and 466, rocker arm 462, follower arm 464 and cam disc 461. More particularly, the rocker arm ,456 is provided with arcuate guideways 463 which are concentric to the pivot connection between the link 451 and the yoke 56 (Fig. 3) when the latter is in the home position in which the needle bar is disposed vertically. Adjustable within the arcuate guideways 483 of the rocker arm 456 is a sliding block 484 to which the link 451 is pivoted as at 485. The sliding block 484 may be secured to the rocker arm 456 in any adjusted position within the guideways 483 in any suitable manner. Thus, the amplitude of-oscillation of the yoke 56 and, consequently, the spacing e of the overlying stitches b (Fig. 1), may be varied as desired. It is even possible to prevent oscillation of the yoke 56 in spite of rotation of the cam disc 461, simply by shifting the sliding block 484 into coaxial alinement with the pivot axis of the rocker arm 456.

As best shown in Fig. 36, the sleeve 458 is provided with an annular groove 486 into which projects the forked end 481 of the member 68 (Fig. 2) which is fed together with the yoke 56 longitudinally of the tack. The rocker arm 456 is thus coupled by the member -68 to the yoke 56 for combined movement longitudinally of the tack. Such movement of the rocker arm 456 does not interfere with the drive of the latter by the axially immovable sleeve 486 because the coupling portions 466 and 48I of said sleeves permit relative axial movement therebetween.

Thread severing and clamping device E Referring more particularly to'Figs. 2, 8 and 31 to 35, inclusive, a star wheel 496, having equiangularly spaced radial arms 492, is pivotally mounted at 493 to thethroat plate I18. Also mounted on the throat plate I18, is a thread cutter 494, a spacer 495 and a thread clamp 496. More particularly, the cutter 494, which is of the shape illustrated in Figs. 32 and 33, is nearest to the throat plate I18 while the spacer 495 is intermediate said cutter and the thread clamp 496. The thread clamp 496 is in reality a leaf spring, and the spacer 495 has an arcuate surface 491 which defines, together with the cutter 494 and the clamp 496, a groove 498 through which the arms 492 of the star wheel 496 are adapted to pass in the manner shown in Figs. 33 to 35, inclusive. It can also be observed from Figs. 33 and 34 that each arm 492 will traverse the throat opening 499 in the throat plate I18 before entering the groove 498.

The operation ofthe thread cutter and clamp is as follows: During the formation of the last stitch b24 (Fig. 1), but prior to the completion thereof, the needle-thread loop I16 assumes during its passage around the shuttle I66 the momentary position illustrated in Fig. 32, and it is at this time thatthe star wheel 496 is indexed a distance equal to the angle between consecutive arms 492. Each of these arms 492 is provided with fingers 566 which are so spaced apart that they catch the forward leg 56I of the needlethread loop I16 and the bobbin thread 562 in the fashion shown in Fig. 32 when one of these arms 492 has been advanced from the position 492a (Fig. 34) into the momentary position shown in Fig. 32. During the continued advance of this arm from the position shown in Fig. 32 into the position 492b, the same draws the caught threads into the groo e 498, whereby the shear edges 563 of the cutter 494 cooperate with said arm 492 to sever the needle thread loop and the bobbin thread. Hence, the needle thread which has been used up in the formation of the lock stitches in the work W, is severed from the supply thread 1 at the shearing edge 563 of the cutter 494, leaving a short length of upper or needle thread extending from the last stitch hole in the work W. Hence, there is no complete lock stitch in the last hole stitched into the work by the needle. Likewise, the bobbin thread, which has been used up in the formation of the lock stitches, is severed at the shearing edge 563, leaving a short length of under or bobbin thread depending from the hole in which the last look stitch has been completed (Fig. 32). The leading or severed end of the bobbin thread supply 562 between the arm 492 and the clamp 496 is, furthermore, clamped between the arm 492 and the clamp 496 in .such manner that the same will be carried against the work by the first loop of needle thread which has been passed around the shuttle I66 on the first reciprocation of the needle 53 during the next cycle of operation of the machine.

In order to index the star wheel 496 at the end of each tacking operation of the machine, a reciprocable pawl 566 is. slidable on a machined fiat surface'561 of the'cam block I 16 (Figs. '31

to 35), androtatable about a pivot 566 .which is guided for linear movement in a groove 566a 116. The pawl 505 is provided with cam surfaces 508, 509, 510 and 511. The cam surfaces 509 to 510, inclusive, are adapted to cooperate with a pin 513 which projects from the cam block 116, while the cam surface 51 l is adapted to cooperate with a pin.514 which projects also from the cam block 116. In the full line position 505a of the pawl as shown in Fig. 33, the same is held in engagement with a machined shoulder 515 of the cam block 116 by means of the floating pivot 506 and through cooperation between the cam surface 510 and the pin 513. It appears also from Fig. 33 that the pawl in the position 505a locks the star wheel 590 against rotation in either direction. On moving the pawl from the position 505a to the right as viewed in Fig. 33, its cam surface 508 will engage the pin 513, whereby said pawl is rocked into the dot and dash line position 5051) (Fig. 34), but not until said pawl has been sufficiently withdrawn into the full line position 5050 (Fig. 34) to clear the star wheel 490 when being rocked into said dotand-dash line position 50%. Now, when the pawl 505 is moved forwardly, i. e., to the left in Fig. 34, the same is locked against any clockwise rotation as viewed in Fig. 34 until saidpawl projects underneath the nearest arm 492 of the star Wheel 490 as shown in .the dot-and-dash line position 505d of the pawl in Fig. 33. More particularly, the pawl 505 is locked against rotation in any direction during its advance from the position 5051) into the position 505d due to the cooperation between its cam surfaces 509 and 511 and thepins 513 and 514, respectively, and by reason of the fact that the floating pivot 506 projects between the pins 513 and 514 until the pawl projects underneath the nearest arm 492 of the star wheel 490. Continued movement of the pawl 505 from the position 505d into the full line position 505a (Fig. 33) will result in a rocking motion of the same in a clockwise direction as viewed in Fig. 33 due to the cooperation between the cam surface 510 and the pin 513. Thus, the star wheel 490 is indexed once during one reciprocation of the pawl 505.

For reciprocating the pawl 505, a link 520 is connected thereto at 506 (Fig. 35). This link 520 is also pivotally connected at-521 with a bell crank lever 522 which is pivotally mounted at 523 (Figs. 8, 9 and 10) on a rack 524, movable in guideways 525 which are provided by a bracket 526 of the horn 51 of the machine and gib plates 521. Interposed between the depending ar-m 528 (Fig. 3) of a cam follower 529 (Fig. 25) and the other arm 530 of the bell crank lever 522, and connected thereto by universal joints 531 (Fig. 8), is a link 532. Meshing with the rack 524 is a spur gear 533 (Figs. 9 and 10) which is keyed as at 534 on a stub shaft 535, journalled in the bracket 526. Mounted on one end of the stub shaft 535 is a rocker arm 536 which is connected by alink 531 with one arm 538 of the double arm rocker 306 (Figs. 2 and 8). Inasmuch as the two arms of the lever 306, which are connected with the links 301 and 531, are identical and diametrically opposite each other, and ina'smuch as the gears 312 and 533 are also identical, it appears, particularly from Fig. 2, that the rack 524 with the bell crank lever 522 and the link 520 are moved through the same distances and in the same directions as the shuttle support and drive 162 when the latter is fed in either direction by either of the feed cams 315 or 316. Inasmuch as the star wheel 490 as well .as the cutter 494 and thread clamp 496 are carried by the throat plate 118 and, hence, also movable together with the shuttle support and drive 162, the elements shown in Figs. 33 and 34 will be maintained in their relative positions and no relative movement between any of these elements takes place while the shuttle support and drive is fed. However, at a certain time in the cycle of operation of the machine and by means of a cam to be described hereafter, the follower 529 will be rocked at first counterclockwise as viewed in Fig. 25 so as to withdraw the pawl 505 from the full line position 505a in Fig. 33 to the dot-and-dash line position 5055 in Fig. 34. Shortly thereafter, the pawl 505 is rocked forwardly into its normal position 5050 again, thereby indexing the star wheel 490 for a cutting and clamping operation which takes place in the previously explained manner.

Control F The present machine is so constructed as to form the tack illustratedin Fig. 1. This particular tack has four superimposed lines a1 to all of underlying stitches a and one row bi of overlying or covering stitches b. For claritys sake, Fig. 1 shows the four lines al to a4 of underlying stitches a side by side, rather than superimposed as they are in reality. Hence, when the machine is started with the needle ele ment 53 and the shuttle element 160 in the home position shown in Figs. 1 and 2, these elements are first advanced step by step in the direction of the arrow 550 (Fig. 1), while at the same time cooperating to form the first line al of underlying stitches a. The step by step forward feed of the elements 53 and 160 in the direction of the arrow 550 is then reversed and these elements are moved step by step in the direction of the arrow 552 (Fig. 1) to form the second line a2 of underlying stitches a. On arrival in the home position, the direction of feed of these elements is again reversed to a step by step forward feed for the formation of the third line a3 of underlying stitches a, said feed to be reversed again to a step by step return feed for the formation of the fourth and last line a4 of underlying stitches a. The alternate forward and return feeds of the elements 53 and 160 up to this point in the cycle of operation of the machine has been derived from the cam element 315, resulting in the comparatively wide spacing c of the underlying stitches a (Fig. 1). For the following formation of the narrowly spaced overlying stitches b, the step by step forward feed in the direction of the arrow 550 is derived from the feed cam 316 (Fig. 13). However, before the needle descends for the first time during this forward feed, the same is shifted to one side (right side in Fig. 1) of the longitudinal axis of the tack a distance which is one-half the width e of the overlying stitches b. Thereafter, the needle is shifted or vibrated the full width e during consecutive needle reciprocations, as can be readily understood. Also, each step during the forward feed of the needle and shuttle elements 53 and 160 takes place on each second needle reciprocation, with the result that each second overlying stitch extends at right angles to the longitudinal axis of the tack. This is by reason of the fact that the feed cam 316 (for the overlying stitches) is rotated at one-half the angular speed of the feed cam 315 (for the underlying stitches). As soon as the overlying stitches b are formed, the direction of feed of the elements 53 and 160 is again reversed. At 

